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Abstract:

Compounds useful as plasticizers and the synthesis thereof are disclosed.
In general, the invention includes mixed alkyl/aryl diesters where the
aryl and alkyl ester moieties are attached to a cyclic structure at
vicinal carbons. The invention also includes synthetic processes of
making such compounds.

Claims:

1. A compound including an asymmetric cyclic ester having the formula (I):
##STR00014## wherein Y is a C5 to C8 cyclic alkyl group,wherein
R1 is a straight chain or branched C2-C18 alkyl
group,wherein W is a straight chain or branched C1-C5 alkyl
group,wherein Ar is a C6-C15 cyclic aryl group having at least
three double bonds, andwherein R1O(O═)C and ArWO(O═)C-- are
attached to vicinal carbons of Y.

2. A blend of the compounds of claim 1 including at least two different
types of at least one of the Y, R1, W, and Ar groups.

3. The compound of claim 1, wherein Y is selected from the group
consisting of cyclohexene, cyclohexane, and combinations thereof.

10. A process of making an asymmetric cyclic ester comprising:a.
contactingi. at least one cyclic dicarboxylic acid anhydride withii. at
least one C2-C18 aliphatic alcohol, in the presence ofiii. a
base to form a reaction mixture andb. contacting the reaction mixture
with a benzyl halide to form a product.

11. The process of claim 10, further comprising, after (a)(iii), step
(a)(iv), wherein step (a)(iv) includes maintaining the reaction mixture
temperature at about 60 to about 130.degree. C.

12. The process of claim 10, further comprising, after (b), step (b)(i),
wherein (b)(i) includes maintaining the reaction mixture temperature at
about 100 to about 180.degree. C.

13. The process of claim 10, further comprising, after (b), step (c),
wherein step (c) comprises washing the product of (b) with water at a pH
of less than 6, followed by (d), washing the product of (c) with water at
a pH of greater than 8, followed by (e), wherein step (e) comprises
washing the product of (d) with water.

14. The process of claim 13, further comprising, after (e), step (f),
wherein step (f) comprises steam stripping the product at a pressure of
less than 500 torr.

15. The process of claim 14, further comprising after (f), step (g),
wherein step (g) comprises stripping the product of moisture at a
pressure of less than 200 torr.

17. The process of claim 10, wherein the at least one cyclic carboxylic
acid anhydride of (a)(i) is selected from the group consisting of
4-cyclohexene-1,2-dicarboxylic acid anhydride and
cyclohexane-1,2-dicarboxylic acid anhydride and combinations thereof, and
wherein the aliphatic alcohol of (a)(ii) is selected from the group
consisting of isononyl alcohol and 2-propylheptyl alcohol, and
combinations thereof.

18. The process of claim 10, wherein the base is selected from the group
consisting of pyridines, tertiary amines, room temperature ionic liquids,
and combinations thereof.

19. A process of making an epoxidized asymmetric cyclic ester
comprising:a. contactingi. a cyclic dicarboxylic anhydride including one
or two unsaturated bonds withii. an aliphatic alcohol, in the presence
ofiii. a base to form a reaction mixtureb. contacting the reaction
mixture of (a) with a benzyl halide or a phenyl-substituted alkyl halide,
to form a second reaction mixture,c. isolating the resulting unsaturated
diester andd. contacting the unsaturated diester with a peracid.

20. A process of making a saturated asymmetric cyclic ester comprising:a.
contactingi. at least one cyclic dicarboxylic anhydride including one or
two unsaturated bonds withii. an aliphatic alcohol, in the presence
ofiii. a base to form a reaction mixture,b. contacting the reaction
mixture of (a) with a benzyl halide or a phenyl-substituted alkyl halide,
to form a second reaction mixture,c. isolating the resulting unsaturated
diester, andd. contacting the unsaturated diester with a hydrogenation
catalyst and hydrogen gas.

21. A process of making a saturated asymmetric cyclic ester comprising:a.
contactingi. at least one cyclic dicarboxylic anhydride withii. benzyl
alcohol or phenyl-substituted alcohol, in the presence of a base to form
a reaction mixture, andb. contacting the reaction mixture of (a) with at
least one C2-C18 alkyl halide to form said mixed diester.

22. A process of making an asymmetric cyclic ester comprising:a.
contactingi. a maleic anhydride withii. an aliphatic alcohol, in the
presence ofiii. a base to form a reaction mixture,b. contacting the
reaction mixture of (a) with a benzyl halide or a phenyl-substituted
alkyl halide, to form an asymmetric maleate diester, andc. contacting the
ester of (b) with a diene to form an asymmetric cyclic ester.

24. The process of claim 22, further comprising contacting the product
with a hydrogenation catalyst and hydrogen gas.

25. The process of claim 22, further comprising contacting the product
with a peracid.

26. A process of making a saturated asymmetric cyclic ester comprising:a.
contactingi. a cyclic dicarboxylic anhydride including one, two or three
unsaturated bonds withii. an aliphatic alcohol, in the presence ofiii. a
base to form a reaction mixture including an asymmetric monoester salt,b.
hydrogenatingi. an asymmetric monoester acid salt formed in (a) in the
presence ofii. a hydrogenation catalyst, to form a reaction mixture,
andc. contacting the reaction mixture of (b) with a benzyl halide or a
phenyl-substituted alkyl halide, to form an asymmetric cyclic ester.

28. A process of making an asymmetric cyclic ester comprising:a.
contactingi. a maleic anhydride withii. a benzyl alcohol or a
phenyl-substituted alcohol, in the presence ofiii. a base to form a
reaction mixture,b. contacting the reaction mixture of (a) with an alkyl
halide to form an asymmetric maleate diester, andc. contacting the ester
of (b) with a diene to form an asymmetric cyclic ester.

30. A process of plasticizing a polymer comprising contacting the
plasticizer of claim 1 with a polymer.

31. A process of plasticizing a polymer comprising contacting the
plasticizer of claim 2 with a polymer.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of Invention

[0002]The invention relates to plasticizers useful in plasticizing
thermoplastic polymers, for example, polyvinyl chloride (PVC). In
particular, the invention relates to asymmetric cyclic esters, having
aryl and alkyl ester moieties attached to a cyclic structure at vicinal
(consecutive) carbons. In many cases, this is carbons in a 1, 2
relationship.

[0003]2. Description of Related Art

[0004]Plasticizers are compounds or mixtures of compounds that are added
to polymer resins to impart softness and flexibility. Phthalic acid
diesters, also called phthalates, are the primary plasticizers for most
flexible polymer products, especially polymer products formed from
polyvinyl chloride (PVC) and other vinyl polymers. Examples of common
phthalate plasticizers include: diisononyl phthalate (DINP), butyl benzyl
phthalate (BBP), and di-2-ethylhexyl-phthalate (DEHP).

SUMMARY OF THE INVENTION

[0005]The invention relates to mixed alkyl/aryl diester compounds useful
in plasticizing polyvinyl chloride (PVC) and other thermoplastic
polymers. In particular, the mixed alkyl/aryl diesters of the invention
are asymmetric cyclic esters where the aryl and alkyl ester moieties are
attached to a cyclic structure at adjacent, or vicinal, carbons.
Preferably the cyclic structure is a six-membered ring, such as a
cyclohexyl group.

[0006]In particular, an embodiment of the invention is a compound
including an asymmetric cyclic ester having the formula (I):

##STR00001##

wherein Y is a C5 to C8 cyclic alkyl group, wherein R1 is a
straight chain or branched C2-C18 alkyl group, wherein W is a
straight chain or branched C1-C5 alkyl group, wherein Ar is a
C6-C15 cyclic aryl group having at least three double bonds,
and wherein R1O(O═)C-- and ArWO(O═)C-- are attached to
vicinal carbons of Y.

[0007]A second embodiment of the invention is a process of making an
asymmetric cyclic ester comprising: (a) contacting (i) at least one
cyclic dicarboxylic acid anhydride with (ii) at least one
C2-C18 aliphatic alcohol, in the presence of (iii) a base to
form a reaction mixture and (b) contacting the reaction mixture with a
benzyl halide or phenyl-substituted alkyl halide to form a product.

[0008]Another embodiment of the invention is a process of making an
epoxidized asymmetric cyclic ester comprising: (a) contacting (i) a
cyclic dicarboxylic anhydride including one or two unsaturated bonds with
(ii) an aliphatic alcohol, in the presence of (iii) a base to form a
reaction mixture, (b) contacting the reaction mixture of (a) with a
benzyl halide or phenyl-substituted alkyl halide, to form a second
reaction mixture, (c) isolating the resulting unsaturated diester and (d)
contacting the unsaturated diester with a peracid.

[0009]Still another embodiment of the invention is a process of making a
saturated asymmetric cyclic ester comprising (a) contacting (i) at least
one cyclic dicarboxylic anhydride including one or two unsaturated bonds
with (ii) an aliphatic alcohol, in the presence of (iii) a base to form a
reaction mixture, (b) contacting the reaction mixture of (a) with a
benzyl halide or phenyl-substituted alkyl halide, to form a second
reaction mixture, (c) isolating the resulting unsaturated diester, and
(d) contacting the unsaturated diester with a hydrogenation catalyst and
hydrogen gas.

[0010]Yet another embodiment of the invention is a process of making a
saturated asymmetric cyclic ester comprising: (a) contacting (i) at least
one cyclic dicarboxylic anhydride with (ii) benzyl alcohol or
phenyl-substituted alcohol, in the presence of a base to form a reaction
mixture, and (b) contacting the reaction mixture of (a) with at least one
C2-C18 alkyl halide to form said mixed diester.

[0011]Still another embodiment of the invention is a process of making an
unsaturated asymmetric cyclic ester comprising: (a) contacting (i) a
maleic anhydride with (ii) an aliphatic alcohol, in the presence of (iii)
a base to form a reaction mixture, (b) contacting the reaction mixture of
(a) with a benzyl halide or phenyl-substituted alkyl halide, to form an
asymmetric maleate diester, and (c) contacting the ester of (b) with a
diene to form an unsaturated asymmetric cyclic ester.

[0012]Yet another embodiment of the invention is a process of making a
saturated asymmetric cyclic ester comprising: (a) contacting (i) a cyclic
dicarboxylic anhydride including one, two or three unsaturated bonds with
(ii) an aliphatic alcohol, in the presence of (iii) a base to form a
reaction mixture including an asymmetric monoester salt, (b) contacting
with hydrogen (i) an unsaturated asymmetric monoester acid salt formed in
(a) in the presence of (ii) a hydrogenation catalyst, to form a reaction
mixture, and (c) contacting the reaction mixture of (b) with a benzyl
halide or phenyl-substituted alkyl halide, to form an asymmetric cyclic
ester.

[0013]Still another embodiment of the invention is a process of making an
unsaturated asymmetric cyclic ester comprising: (a) contacting (i) a
maleic anhydride with (ii) a benzyl alcohol or phenyl-substituted
alcohol, in the presence of (iii) a base to form a reaction mixture, (b)
contacting the reaction mixture of (a) with an alkyl halide to form an
asymmetric maleate diester, and (c) contacting the ester of (b) with a
diene to form an unsaturated asymmetric cyclic ester.

[0014]Another embodiment of the invention is a process of making a
1,2-cyclic alkyl/aryl mixed diester comprising (a) contacting at least
one (i) cyclic dicarboxylic anhydride with (ii) a C2-C18 alkyl
alcohol, in the presence of (iii) a trialkyl amine to form a reaction
mixture and (b) contacting the reaction mixture with a benzyl halide or
phenyl-substituted alkyl halide to form a product.

[0015]Still another embodiment of the invention is a process of making an
epoxidized 1,2-cyclic alkyl/aryl mixed diester comprising: (a) contacting
(i) a cyclic compound selected from the group consisting of (1) a cyclic
dicarboxylic acid and (2) a cyclic dicarboxylic anhydride and
combinations thereof with (i) an alkyl alcohol, in the presence of (ii) a
trialkyl amine to form a reaction mixture and (iii) contacting the
reaction mixture of (a) with a benzyl halide or phenyl-substituted alkyl
halide, to form a second reaction mixture, (b) isolating the resulting
unsaturated diester and (c) contacting the unsaturated diester with a
peracid.

[0016]Yet another embodiment of the invention is a process of making a
saturated 1,2-cyclic alkyl/aryl mixed diester comprising: (a) contacting
(i) at least one cyclic dicarboxylic anhydride with (ii) an alkyl
alcohol, in the presence of (iii) a trialkyl amine to form a reaction
mixture (b) contacting the reaction mixture of (a) with a benzyl halide
or phenyl-substituted alkyl halide, to form a second reaction mixture,
(c) isolating the unsaturated diester, and (d) contacting the unsaturated
diester with a hydrogenation catalyst and hydrogen gas.

[0017]An embodiment of the invention is a process of making a saturated
1,2-cyclic alkyl/aryl mixed diester comprising: (a) contacting (i) at
least one cyclic dicarboxylic anhydride with (ii) benzyl alcohol or
phenyl-substituted alcohol, to form a benzyl half-ester, and (b)
contacting the benzyl half ester with (i) a C2-C18 alkyl halide
in the presence of (ii) a trialkyl amine to form said mixed diester.

[0018]The invention further relates to processes of making plasticized
thermoplastic polymers including the addition of any plasticizer herein
to a thermoplastic polymer.

[0019]The foregoing and other features of the invention are hereinafter
more fully described and particularly pointed out in the claims, the
following description setting forth in detail certain illustrative
embodiments of the invention, these being indicative, however, of but a
few of the various ways in which the principles of the invention may be
employed.

DETAILED DESCRIPTION OF THE INVENTION

[0020]The compounds of the invention are used to soften thermoplastic
polymer resins that would otherwise be brittle and inappropriate for many
applications. Plasticizers improve flexibility and tensile strength in
such resins.

[0022]In particular, an embodiment of the invention is a compound
including an asymmetric cyclic ester having the formula (I):

##STR00002##

wherein Y is a C5 to C8 cyclic alkyl group, wherein R1 is a
straight chain or branched C2-C18 alkyl group, wherein W is a
straight chain or branched C1-C5 alkyl group, wherein Ar is a
C6-C15 cyclic aryl group having at least three double bonds,
and wherein R1O(O═)C-- and ArWO(O═)C-- are attached to
vicinal carbons of Y.

[0023]A general scheme for synthesizing compounds of this invention
includes two critical steps. The first (Reaction 1) is ring opening of
the anhydride with an alcohol to form an ester and formation of a salt
with the concomitantly formed acid.

##STR00003##

The other critical step (Reaction 2) is the formation of the second ester
by reacting the salt with an alkyl halide.

##STR00004##

Other intermediate steps may be involved, but the two foregoing reaction
steps are common to the general scheme.

[0024]The W--Ar group of formula (I) may be derived from either an alcohol
in Reaction 1 or from a phenyl-substituted alkyl halide in Reaction 2.
Phenyl-substituted alkyl halides [X--W--Ar] that are useful in preparing
compounds of this invention include: benzyl halide,
1-halo-1-phenylethane, 1-halo-2-phenylethane, 4-phenyl butyl halide, and
others. The corresponding alcohols are useful for introducing the aryl
group in Reaction 1.

##STR00005##

[0025]The central ringed group Y may be selected from a variety of 5, 6,
7, or 8 membered rings or bicyclic systems. The group Y may include one
or more substituents including, for example, methyl, ethyl, propyl,
bridging methylene, bridging ethylene, hydroxyl, bridging oxygen,
carboxylic acid, acetyl and others. Preferably, Y is a six-membered ring,
based on cyclohexane, which may be unsaturated or substituted, or both
(in blends), singly or multiply. Y may also be an epoxidized cyclohexane,
a five membered ring such as cyclopentadiene, cyclopentene, or
cyclopentane, a seven membered ring such as cycloheptadiene,
cycloheptene, or cycloheptane, or an eight membered ring including
cyclooctane and the various polyunsaturated forms of cyclooctane.

[0026]In particular, the group Y is preferably selected from the group
consisting of cyclohexene, cyclohexane, and combinations thereof. The
group Y may also be epoxidized cyclohexane, i.e, cyclohexene oxide.

[0029]The aliphatic alcohols (which donate the R1 group of the
inventive diesters) used in forming the asymmetric cyclic esters of the
invention can (but need not) be halogenated. Such alcohols can be linear,
branched, or have cyclic moieties. Preferably, the aliphatic alcohols
contain 2 to about 18 carbon atoms, more preferably 4 to 10 carbon atoms,
and most preferably 5 to 9 carbon atoms. Alternatively, the alcohols may
include 2 to 8 carbons. Suitable aliphatic alcohols include, for example,
ethanol, bromoethanol, n-propanol, isopropanol, 2-chloropropanol,
3-chloropropanol, 2-methylpropanol, 2-ethylpropanol, n-butanol,
isobutanol, tert-butanol, 2-methylbutanol, 3-methylbutanol,
2-ethylbutanol, 2,2-dimethylbutanol, 2,3-dimethylbutanol,
3,3-dimethylbutanol, 2-methylpentanol, 3-methylpentanol,
4-methylpentanol, 2-ethylpentanol, 3 ethylpentanol, 4-ethylpentanol,
cyclopentyl ethanol, cyclopentyl propanol, cyclopentyl hexanol,
cyclopentyl butanol, cyclopentyl pentanol, cyclohexanol, cyclohexyl
ethanol, 2-ethylhexanol, n-nonanol, isononanol, tert-nonanol, decanol,
undecanol, propylheptanol, dodecanol, oleyl alcohol and stearyl alcohol.
The various forms of nonanol and decanol are preferred, and isononanol
and 2-propylheptanol are most preferred. Other aliphatic alcohols not
named herein and other forms of alkyl alcohols named herein are also
suitable, provided they have no more than 18 carbons.

[0030]Preferably, R1 includes 2 to about 18 carbon atoms, more
preferably 4 to 10 carbon atoms, for example C4 to C10 straight
chain or branched alkyl groups, and more preferably 5 to 9 carbon atoms.
A blend of compounds having different embodiments of general Formula I,
having any of the Y, R1, W, and Ar groups disclosed herein is
envisioned, in any combination.

[0031]The W group includes 1 to 5 carbon atoms, preferably 1 or 2 carbon
atoms, and more preferably one carbon atom. The W group is provided by
alkyl groups attached to the Ar group, in the reactant Ar--W--X, which
participates in the esterification reactions disclosed herein. The
formula Ar--W--X can stand for a benzyl halide, an alkyl substituted
benzyl halide, or a phenyl substituted alkyl halide.

[0032]The aryl reactants (which donate the Ar group of the inventive
diesters) used in the esterification reaction mixture have one or more
aromatic rings. Various substituents, including alkyl groups, may be
present on the rings. Accordingly, the group Ar may be selected from the
group consisting of benzene; methylbenzene; dimethyl benzene, ditertiary
butyl benzene; napththalene, anthracene, cumene and combinations thereof.

[0035]Catalyst. A catalyst is advantageously employed in the
esterification reaction(s) of the invention. The catalyst is typically a
base, preferably an organic base. Suitable organic bases include
pyridines, tertiary amines, room temperature ionic liquids, and
combinations thereof. Tertiary amines are preferred. Tertiary amines for
use in the process of the invention can be represented by the structure
R2R3R4N where R2-R4 may be the same or different
alkyl radicals. Examples of suitable trialkyl amines include
trimethylamine, triethylamine, tripropylamine, tributylamine,
tripentylamine, trihexylamine, triheptylamine, trioctylamine,
trinonylamine, as well as the normal-, iso-, and tert-configurations of
the foregoing, if appropriate. Various combinations of R2-R4
where R2-R4 can be individually selected from methyl, ethyl,
propyl, butyl, hexyl, heptyl, octyl, nonyl, decyl are also possible.
Other amines suitable herein include triisoamylamine, methyldiethylamine,
dimethylethylamine, dimethylcyclohexylamine, dimethylhexylamine,
diethylhexylamine, dimethyldecylamine and others. The preferred amine is
triethylamine.

[0036]Pyridines are six-membered heterocycles having 5 carbon atoms and
one nitrogen atom in the ring. Pyridine itself has the formula
C5H5N, and can be formed by the following reaction:

##STR00006##

By substituting other aldehydes for acetaldehyde, one obtains alkyl and
aryl substituted pyridines.

[0037]An ionic liquid is a liquid that contains essentially only ions.
Some ionic liquids, such as ethylammonium nitrate are in a dynamic
equilibrium where at any time more than 99.99% of the liquid is made up
of ionic rather than molecular species. Broadly the term includes molten
salts, for instance, sodium chloride at temperatures higher than
800° C. Salts that are liquid at room temperature are called
room-temperature ionic liquids, or RTILs.

[0038]Another embodiment of the invention is a process of making an
asymmetric cyclic ester comprising: (a) contacting (i) at least one
cyclic dicarboxylic acid anhydride with (ii) at least one
C2-C18 aliphatic alcohol, in the presence of (iii) a base to
form a reaction mixture and (b) contacting the reaction mixture with a
benzyl halide or phenyl-substituted alkyl halide to form a product. An
illustrative example of this process is depicted in Reaction 3, where
cyclohexane-1,2-dicarboxylic anhydride, triethylamine and benzyl chloride
are used specifically.

##STR00007##

[0039]The process may further comprise, after (a)(iii), step (a)(iv),
wherein step (a)(iv) includes maintaining the reaction mixture
temperature at about 60 to about 130° C. The process may further
comprise, after (b), step (b)(i), wherein (b)(i) includes maintaining the
reaction mixture temperature at about 100 to about 180° C. The
process may further comprise, after (b), step (c), wherein step (c)
comprises washing the product of (b) with water at a pH of less than 6,
followed by (d), washing the product of (c) with water at a pH of greater
than 8, followed by (e), wherein step (e) comprises washing the product
of (d) with water. The process may further comprise, after (e), step (f),
wherein step (f) comprises steam stripping the product at a pressure of
less than 500 torr, preferably less than 400 torr. The process may yet
further include, after (f), step (g), wherein step (g) comprises
stripping the product of moisture at a pressure of less than 200 torr,
preferably less than 100 torr.

[0041]In another preferred embodiment of the process, the at least one
cyclic carboxylic acid anhydride is selected from the group consisting of
4-cyclohexene-1,2-dicarboxylic acid anhydride and
cyclohexane-1,2-dicarboxylic acid anhydride and combinations thereof, and
the aliphatic alcohol is selected from the group consisting of isononyl
alcohol and 2-propylheptyl alcohol, and combinations thereof. The process
may utilize any base disclosed elsewhere herein, in any combination.

[0042]Another embodiment of the invention is a process of making an
epoxidized asymmetric cyclic ester comprising: (a) contacting (i) a
cyclic dicarboxylic anhydride including one or two unsaturated bonds with
(ii) an aliphatic alcohol, in the presence of (iii) a base to form a
reaction mixture, (b) contacting the reaction mixture of (a) with a
benzyl halide or phenyl-substituted alkyl halide, to form a second
reaction mixture, (c) isolating the resulting unsaturated diester and (d)
contacting the unsaturated diester with a peracid. An illustrative
example of this process is depicted in Reaction 4, where
4-cyclohexene-1,2-dicarboxylic anhydride, triethylamine and benzyl
chloride are used specifically.

##STR00008##

[0043]Peracids. Peracids, or peroxyacids, are excellent epoxidizing
agents. For the organic peracids, there is an extra oxygen atom between
the carbonyl group and their acidic hydrogen, making them electrophilic
towards oxygen. Inorganic peracids include perchloric acid, HClO4 or
perbromic acid, HBrO4. Attack at the oxygen position by a
nucleophile displaces carboxylate, which is a good leaving group. An
example of one such reaction involves ethylene and peroxyformic acid, or
more appropriately for the invention, the reaction between benzyl
isononyl cyclohex-4-ene and a peracid such as m-chloroperbenzoic acid.
Other suitable peracids herein include peracetic acid
(CH3C(═O)OOH), and perbenzoic acid (C6H5C(═O)OOH).
The peracid can be formed in situ from the addition of hydrogen peroxide
to an acid, e.g. formic acid and hydrogen peroxide will form performic
acid (HC(═O)OOH) within a reaction mixture. The reaction mechanism is
essentially an electrophilic attack, with a proton being transferred from
the epoxide oxygen to the carboxylic acid by-product. First, the
nucleophilic π (pi-) bond donates its electrons to the oxygen,
breaking the O--O bond to form the new carbonyl bond. The electrons from
the old O--H bond make up the second new C--O bond, and the original
carbonyl group uses its electrons to pick up the proton.

[0044]Still another embodiment of the invention is a process of making a
saturated asymmetric cyclic ester comprising (a) contacting (i) at least
one cyclic dicarboxylic anhydride including one or two unsaturated bonds
with (ii) an aliphatic alcohol, in the presence of (iii) a base to form a
reaction mixture, (b) contacting the reaction mixture of (a) with a
benzyl halide or phenyl-substituted alkyl halide, to form a second
reaction mixture, (c) isolating the resulting unsaturated diester, and
(d) contacting the unsaturated diester with a hydrogenation catalyst and
hydrogen gas. An illustrative example of this process is depicted in
Reaction 5, where 4-cyclohexene-1,2-dicarboxylic anhydride, triethylamine
and benzyl chloride are used specifically.

##STR00009##

[0045]Yet another embodiment of the invention is a process of making a
saturated asymmetric cyclic ester comprising: (a) contacting (i) at least
one cyclic dicarboxylic anhydride with (ii) benzyl alcohol or
phenyl-substituted alcohol, in the presence of a base to form a reaction
mixture, and (b) contacting the reaction mixture of (a) with at least one
C2-C18 alkyl halide to form said mixed diester. An illustrative
example of this process is depicted in Reaction 6, where
cyclohexane-1,2-dicarboxylic anhydride, triethylamine and benzyl alcohol
are used specifically.

##STR00010##

[0046]Still another embodiment of the invention is a process of making an
asymmetric cyclic ester comprising: (a) contacting (i) a maleic anhydride
with (ii) an aliphatic alcohol, in the presence of (iii) a base to form a
reaction mixture, (b) contacting the reaction mixture of (a) with a
benzyl halide or phenyl-substituted alkyl halide, to form an asymmetric
maleate diester, and (c) contacting the ester of (b) with a diene to form
an asymmetric cyclic ester. In a preferred embodiment, the diene is
selected from the group consisting of butadiene; 3-sulfolene; isoprene;
1,3-pentadiene; cyclopentadiene; furan; 1-methoxybutadiene;
1,3-hexadiene; 3-methyl-1,3-pentadiene; 4-methyl-1,3-pentadiene;
1,3-cyclohexadiene; sorbic acid esters; ethyl sorbate;
1,2,3,4,5-pentamethylcyclopentadiene; myrcene
(7-methyl-3-methylene-1,6-octadiene); and combinations thereof. An
illustrative example of this process is depicted in Reaction 7, where
maleic anhydride, triethylamine, benzyl chloride, and 1,3-butadiene are
used specifically.

##STR00011##

[0047]This process may further comprise contacting the unsaturated
asymmetric cyclic ester product with a hydrogenation catalyst and
hydrogen gas. This process may yet further include contacting the
unsaturated asymmetric cyclic ester product with a peracid.

[0048]An embodiment of the invention is a process of making a saturated
asymmetric cyclic ester comprising: (a) contacting (i) a cyclic
dicarboxylic anhydride including at least one unsaturated bond with (ii)
an aliphatic alcohol, in the presence of (iii) a base to form a reaction
mixture including an asymmetric monoester salt, (b) contacting with
hydrogen (i) an unsaturated asymmetric monoester acid salt formed in (a)
in the presence of (ii) a hydrogenation catalyst, to form a reaction
mixture, and (c) contacting the reaction mixture of (b) with a benzyl
halide or phenyl-substituted alkyl halide, to form an asymmetric cyclic
ester. In a preferred embodiment of this process, the cyclic dicarboxylic
anhydride is phthalic anhydride. Illustrative examples of this process
are depicted in Reaction 8 and Reaction 9.

##STR00012##

[0049]Another embodiment of the invention is a process of making an
asymmetric cyclic ester comprising: (a) contacting (i) a maleic anhydride
with (ii) a benzyl alcohol or a phenyl-substituted alcohol, in the
presence of (iii) a base to form a reaction mixture, (b) contacting the
reaction mixture of (a) with an alkyl halide to form an asymmetric
maleate diester, and (c) contacting the ester of (b) with a diene to form
an asymmetric cyclic ester. In a preferred embodiment of the process, the
diene may be selected from the group consisting of butadiene;
3-sulfolene; isoprene; 1,3-pentadiene; cyclopentadiene; furan;
1-methoxybutadiene; 1,3-hexadiene; 3-methyl-1,3-pentadiene;
4-methyl-1,3-pentadiene; 1,3-cyclohexadiene; sorbic acid esters; ethyl
sorbate; myrcene (7-methyl-3-methylene-1,6-octadiene);
1,2,3,4,5-pentamethylcyclopentadiene; and combinations thereof. An
illustrative example of this process is depicted in Reaction 10.

##STR00013##

[0050]Another embodiment of the invention is a process of making a
1,2-cyclic alkyl/aryl mixed diester comprising (a) contacting (i) at
least one cyclic dicarboxylic acid anhydride with (ii) a C2-C18
alkyl alcohol, in the presence of (iii) a trialkyl amine to form a
reaction mixture and (b) contacting the reaction mixture of (a) with a
benzyl halide or phenyl-substituted alkyl halide, to form a product. The
reaction mixture may optionally be heated after the trialkyl amine is
fully added to the cyclic dicarboxylic acid or anhydride and the alcohol.
After full reaction, the process may further comprise washing the product
with water at a pH of less than 6, followed by washing the product of
with water at a pH of greater than 8. The product may also be washed with
plain water such as tap water, distilled water or deionized water. After
washing, the product may be steam stripped at a pressure of less than 500
torr, and also the moisture may be removed by stripping at a pressure of
less than 200 torr.

[0051]In a preferred embodiment of the process, the cyclic compound is
1,2-dicarboxy cyclohex-4-ene anhydride and the aliphatic alcohol is
isononyl alcohol.

[0052]Still another embodiment of the invention is a process of making an
epoxidized asymmetric cyclic ester comprising: (a) contacting (i) a
cyclic dicarboxylic anhydride including one or two unsaturated bonds with
(ii) an aliphatic alcohol, in the presence of (iii) a base to form a
reaction mixture, (b) contacting the reaction mixture of (a) with a
benzyl halide or phenyl-substituted alkyl halide, to form a second
reaction mixture, (c) isolating the resulting unsaturated diester and (d)
contacting the unsaturated diester with a peracid.

[0053]A further embodiment of the invention is a process of making a
saturated 1,2-cyclic alkyl/aryl mixed diester comprising: (a) contacting
(i) at least one cyclic dicarboxylic anhydride with (ii) an alkyl
alcohol, in the presence of (iii) a trialkyl amine to form a reaction
mixture, (b) contacting the reaction mixture of (a) with a benzyl halide
or phenyl-substituted alkyl halide, to form a second reaction mixture,
(c) isolating the resulting saturated diester, and (d) contacting the
saturated diester with a hydrogenation catalyst and hydrogen gas.

[0054]Yet another embodiment of the invention is a process of making a
saturated 1,2-cyclic alkyl/aryl mixed diester comprising: (a) contacting
(i) at least one cyclic dicarboxylic anhydride with (ii) benzyl alcohol
or phenyl-substituted alcohol, to form a benzyl half-ester, and (b)
contacting the benzyl half ester with (i) a trialkyl amine and then (ii)
a C2-C18 alkyl halide to form said mixed diester.

[0055]The asymmetric cyclic esters of this invention are predominantly of
the cis-configuration. Isomerization of the predominant cis-form to a
predominant trans-form can be effected using methods such as disclosed in
U.S. Pat. No. 5,231,218.

[0056]Another embodiment of the invention is a process of plasticizing a
polymer comprising contacting any compound disclosed herein with a
polymer.

[0057]The asymmetric cyclic esters of this invention can be combined with
other known plasticizers to formulate a plasticizer package to be used in
making plasticized thermoplastic polymers. Examples of known plasticizers
that might be used in conjunction with a plasticizer of the invention
include, without limitation, the following.

[0070](m) Other plasticizers not falling into one of the above categories,
such as alkyl pyrrolidones surfactants, alkyl imidazoles, N-alkyl
hexahydrophthalimide, dibutyl fumarate, dioctyl fumarate, linear alkyl
benzenes, and mineral oil.

[0071]The following experimental examples serve to illustrate, and not
limit, the scope of the invention. Example 1. A one-liter four-necked
round bottom flask was charged with 152 g of
4-cyclohexene-1,2-dicarboxylic acid anhydride and 152 g of isononyl
alcohol. A 250 ml addition funnel was charged with 107 g of
triethylamine, and a 125 ml addition funnel was charged with 134 g of
benzyl chloride. The reaction was blanketed with nitrogen. The reaction
was agitated at 250 RPM, and one third of the triethylamine was added to
the reaction. The reaction was heated to 125° C. and was stirred
at 125° C. for 5 minutes. The reaction was then cooled to
100° C., and the rest of the triethylamine was added to the
reaction. The reaction was stirred at 100-105° C. for 5 minutes.

[0072]The agitation was increased to 300 RPM and the reaction was heated
to 120° C. The addition of the benzyl chloride was started
dropwise. The reaction temperature rose upon the addition of the benzyl
chloride. The temperature was then controlled at 145° C. The
addition of the benzyl chloride was completed over 30 minutes. The
reaction was then stirred for an additional 90 minutes after the addition
of the benzyl chloride was completed.

[0073]The product was washed first with 100 g of water at a pH of 2 and
then with 100 g of water at a pH of 12. The product was then washed with
100 g of water. The material was steam stripped at 125° C. at 80
mm Hg pressure. The product was then stripped of water at 125° C.
at 50 mm Hg to give 328.1 g (85%) of benzyl isononyl
4-cyclohexene-1,2-dicarboxylate.

[0074]Example 2. Using the procedure of Example 1, 145 g of
1,2-cyclohexanedicarboxylic anhydride were reacted with 144 g of isononyl
alcohol and 128 g of benzyl chloride to give 338 g (96.5%) of benzyl
isononyl cyclohexane-1,2-dicarboxylate.

[0075]Example 3. Using the procedure of in Example 1, 153 g of
4-cyclohexene-1,2-dicarboxylic acid anhydride were reacted with 78 g of
butanol and 134 g of benzyl chloride to yield 283 g (95.1%) of benzyl
butyl 4-cyclohexene-1,2-cbuoxyilate.

[0076]Example 4. Using the procedure of Example 1, 103 g of
1,2-cyclohexanedicarboxylic anhydride were reacted with 52 g of butanol
and 90 g of benzyl chloride to yield 191 g (90.1%) of benzyl butyl
cyclohexane-1,2-dicarboxylate.

[0078]Example 6. Using the procedure of Example 1, 153g of
1,2-cyclohexanedicarboxylic anhydride were reacted with 166 g of
2-propylheptyl alcohol and 134 g of benzyl chloride to yield 382 g
(89.9%) of benzyl 2-propylheptyl cylcohexane-1,2-dicarboxylate.

[0079]Example 7. A solution of 47.5 g of m-chloroperbenzoic acid in 511 g
of chloroform was placed in a 1 L round bottom flask. The solution
temperature was kept between 25-35° C. by means of a water bath
while 99.88 g of the product of Example 1 was added dropwise to the
chloroform solution over the course of 2 hours. The reaction was stirred
at 25° C. overnight, i.e., ˜12 hours. The next day the
reaction solution was filtered and was extracted with 100 g of 10% sodium
bicarbonate solution. The chloroform was then removed under vacuum to
give 100.55 g of the epoxidized product, benzyl isononyl
4,5-epoxycyclohexane-1,2-dicarboxylate.

[0080]Example 8. A Parr stirred pressure reactor was charged with 97.44 g
of the product of Example 5 and 0.98 g of 5% Pt on carbon. The reactor
was sealed and purged with nitrogen. The reactor was then heated to
42° C. and was pressurized to 100 psig with hydrogen. The reactor
was stirred for 4.5 hours while maintaining the temperature at 42°
C. and hydrogen pressure at 100 psig. The reactor was cooled to room
temperature and the excess pressure was released. The reaction product
was filtered through Celite to give 73.9 g (75%) of product. GC analysis
of the product indicated that 89.8% of the product benzyl 2-propylheptyl
cyclohexane-1,2-dicarboxylate.

[0081]Example 9. A 1 L four-necked round bottom flask was charged with
152.76 g of 4-cyclohexene-1,2-dicarboxylic anhydride and 153.77 g of
isononyl alcohol. A 250 ml addition funnel was charged with 106.77 g of
triethylamine. The reaction was blanketed with nitrogen. The reaction was
agitated at 250 RPM and one-third of the triethylamine was added to the
reaction. The reaction quickly rose to 125° C. The reaction was
stirred at 125±2° C. for 5 minutes. The reaction was then
cooled to 100° C., and the rest of the triethylamine was added to
the reaction. The reaction was stirred at 100-105° C. for 5
minutes before it was cooled to room temperature to give 407.34 g (98.6%)
of monoisononyl ester of 4-cyclohexene-1,2-dicarboxylic acid
triethylamine salt.

[0082]Example 10. A Parr stirred pressure reactor was charged with 98.92 g
of the product of Example 9 and 1.00 g of 5% Pt on carbon. The reactor
was sealed and purged with nitrogen. The reactor was then heated to
38° C. and was pressurized to 100 psig with hydrogen. The reactor
was stirred for 4.5 hours while maintaining the temperature at 42°
C. and hydrogen pressure at 100 psig. The reactor was cooled to room
temperature and the excess pressure was released. The reaction product
was filtered through Celite to give 96.55 g (96.9%) of product. GC
analysis of the product indicated that 91.3% of the product was the
monoisononyl ester of cyclohexane-1,2-dicarboxylic acid triethylamine
salt.

[0083]Example 11. A 1 L reactor was charged with 270.50 g of material
prepared as described in Example 10. The agitation was set at 300 RPM and
the reaction was heated to 120° C. The addition of the benzyl
chloride was started drop wise. The reaction temperature rose upon the
addition of the benzyl chloride, and the temperature was then controlled
at 145° C. The addition of the benzyl chloride was completed over
30 minutes. After the addition was complete, the reaction was stirred for
an additional 90 minutes. The reaction was cooled to 100° C., and
the product was washed first with 100 g of water at a pH of 2 and then
with 100 g of water at a pH of 12. The product was then washed with 100 g
of water. The material was steam stripped at 125° C. at 80 mm Hg
pressure. The product was then stripped of water at 125° at 50 mm
Hg to give 126.72 g (50.5%) of benzyl isononyl
cyclohexane-1,2-dicarboxylate.

[0084]Example 12. A 1 L four-necked round bottom flask was charged with
166.3 g of 4-methyl-4,5-cyclohexene-1,2-dicarboxylic anhydride and 152.18
g of isononyl alcohol. A 250 ml addition funnel was charged with 107 g of
triethylamine, and a 125 ml addition funnel was charged with 134 g of
benzyl chloride. The reaction was blanketed with nitrogen. The reaction
was agitated at 250 RPM, and one third of the triethylamine was added to
the reaction. The reaction was heated to 125° C. and was stirred
at 125° C. for 5 minutes. The reaction was then cooled to
100° C., and the rest of the triethylamine was added to the
reaction. The reaction was stirred at 100-105° C. for 5 minutes.
The agitation was increased to 300 RPM and the reaction was heated to
120° C. The addition of the benzyl chloride was started drop wise.
The reaction temperature rose upon the addition of the benzyl chloride.
The temperature was then controlled at 145° C. The addition of the
benzyl chloride was completed over 30 minutes. The reaction was then
stirred for an additional 90 minutes after the addition of the benzyl
chloride was completed. The product was washed first with 100 g of water
at a pH of 2 and then with 100 g of water at a pH of 12. The product was
then washed with 100 g of water. The material was steam stripped at
125° C. at 80 mm Hg pressure. The product was then stripped of
water at 125° C. at 50 mm Hg to give 328.1 g (85%) of benzyl
isononyl 4-methyl-4,5-cyclohexene-1,2-dicarboxylate.

[0085]Example 13. A 500 ml four-necked round bottom flask, fitted with a
mechanical agitator, was charged with 104.24 g of
1,2-cyclohexanedicarboxylic anhydride and 88.95 g of 2-ethylhexanol. To
this assembly were added a thermocouple and Friedrichs condenser with
nitrogen inlet. A 250 ml addition funnel charged with 69.77 g of
triethylamine, and another 250 ml addition funnel charged with 96.05 g of
1-chloro-1-phenylethane (93.6% purity by GC) were connected via a Claisen
adapter to the assembly. The reaction was blanketed with nitrogen. The
reaction was stirred and one-third of the triethylamine was added to the
reaction. The reaction quickly rose to 120° C. The reaction was
then cooled to 99° C. over 10 minutes. Then the remainder of the
triethylamine was added to the reaction. The reaction was stirred at
90° C. for 10 minutes. Addition of 1-chloro-1-phenylethane took 8
minutes after which the reaction temperature was 89° C. With
heating the reaction temperature rose to 142° C. over 38 minutes
whereupon salts were visible in the reaction mixture. Reaction was
maintained at 142° C. for 2 hours before it was cooled to
110° C. Water (100 ml) was added and the mixture acidified to a pH
of <4.5. The organic layer was washed with 200 ml water. The organic
was then treated with 150 ml water and 50% NaOH (11.6 g) to give a
mixture with a pH of >9. The organic layer was again washed with 200
ml water. The organic portion was steam stripped at 123-4° C. at
50 mm Hg pressure. Water was distilled from the product at up to
132° C. at 50 mm Hg to give 183.1 g (70%) of 2-ethylhexyl
1-phenylethyl cyclohexane-1,2-dicarboxylate that was of 93.3% purity by
GC.

[0086]Comparative Testing: Benzyl isononyl 4-cyclohexene-1,2-dicarboxylate
(Compound A) and benzyl isononyl cyclohexane-1,2-dicarboxylate (Compound
B) are useful in some of the same applications as butyl benzyl phthalate
(BBP). The inventive compounds were compared to three known plasticizer
products: BBP, a fast fusing phthalate, commercially available from Ferro
Corporation, Cleveland, Ohio, as Santicizer® 160; di-isononyl
phthalate (DINP), a widely used phthalate; and diisononyl
cyclohexane-1,2-dicarboxylate (DINCH), commercially available from BASF
Corporation of Florham Park, N.J., as Hexamoll® DINCH.

[0089]The inventive products COMPOUND A and COMPOUND B outperformed DINCH
in all tests except cold flex temperature. The products performed between
BBP and DINP in all the tests; outperforming DINP with faster fusion
time, softer Shore A, and far lower kerosene extraction, and
outperforming BBP in cold flex and having lower volatility.

[0090]It will be appreciated that although the examples herein primarily
concern a plasticizer for use in PVC resins, the use of the compositions
disclosed herein is also envisioned with a variety of thermoplastic
polymer resins, elastomers, and thermoplastic elastomer compositions.

[0091]Additional advantages and modifications will readily occur to those
skilled in the art. Therefore, the invention in its broader aspects is
not limited to the specific details and illustrative example shown and
described herein. Accordingly, various modifications may be made without
departing from the spirit or scope of the general invention concept as
defined by the appended claims and their equivalents.